Test 3 Notes 33

Test 3 Notes 33 - Pests of Plants Messages: o All plants...

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Pests of Plants Messages: o All plants are susceptible to attack by insects (some plants more than others) o Insect damage to plants is a serious economic concert o Insects can attack different parts of plants and do so in a number of ways o Some insects carry plant disease or make a plant more susceptible to disease o Global issue: insect damage to plants is a major economic factor everywhere and affects many continents and people Examples of Losses from Insect Damage to Plants: o In all of US the Mediterranean Fruit fly damages nuts, fruits, vegetables 1.5 billion How do plants grow? o Most plants begin from seeds. Sometimes they grow from roots of older plants o Roots Take up moisture and nutrients o Stems Translocate water and nutrients to leaves (xylem: takes up H 2 O through roots) and food to fruits and growth tissue (phloem: distributes H 2 O throughout plant) o Leaves Take in light that generate food production and growth (photosynthesis); respiration o Flower Pollinated (fertilized) – produces seed o Fruit Protects seeds and aids in dispersal Types of Injury to Plants: o Seed/fruit feeder Reduce yield by feeding directly on fruit or seed Major problem if we want the fruit/seed (e.g. corn earworm on ears of corn) Minor Problem if we don’t (e.g. insects feeding on spinach seeds, while we eat only the leaves) Ex: fruit fly, coneworm, oak acorn weevil o Sap feeder (Fluid Feeders) Mouthparts like hypodermic needle (milkweed bug) Feed on plant sap – usually phloem: contains the sugars produced by photosynthesis, and many insects, such as aphids, can remove them Rob plants of nourishment Also transmit diseases o Stem feeder o Root feeder o Leaf feeder: remove leaf area from a plant Most plants maximize their leaf areas to maximize the amount of sugars produced by photosynthesis for use in making new progeny (seeds) Leaf feeding insects reduce the overall level of sugar accumulation, which is needed for shoot and root growth, and fruit production Examples: Japanese beetle and Bean leaf beetle Bottom Line: TAKING AWAY LEAF AREA (WHERE PHOTO. TAKES PLACE) Specialized type of leaf feeding: LEAF MINING
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Leaf miners eat tissue between outer layers, destroying cells that conduct photosynthesis, turning leaves brown Ex: Birch leaf miner and elm leaf minder Locust leaf miner, found in VT area, however not bad o Borers Bore into stem. This weakens plant structurally; also inhabits or eliminates transport of water and nutrients Also found in trees (trunks, limbs, and stems) as well as small plants Insects can detect when trees are stressed and invade them Larvae pupate adults come out of holes Types of Injury to plants Bark and Engraver Beetles Specialized borers. Feed on phloem just beneath bark. Affect the flow of nutrients,
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This note was uploaded on 04/11/2008 for the course ENT 2004 taught by Professor Jrvoshell during the Spring '07 term at Virginia Tech.

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Test 3 Notes 33 - Pests of Plants Messages: o All plants...

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